Field of the Invention
The present invention relates to a pneumatic tire, and in particular, relates to a pneumatic tire used for traveling on mud terrain.
Description of the Related Art
Pneumatic tires for four-wheel drive vehicle tend to have an opportunity for traveling not only on the street, but also on loose mud terrain. Thus, such pneumatic tires are requested to an improved mud terrain performance that offers large traction force on mud terrain.
Conventionally, a pneumatic tire having a tread portion provided with grooves with large groove volume is proposed in order to improve mud terrain performance. However, the pneumatic tire described above tends to generate large noise during traveling on dry asphalt roads due to compressed air in such grooves maximized in groove volume.